Gearbox Oil Recommendation - S1

You car is 800 cars newer than my '66. I use Royal Purple 75W-90 (spec is 80W-90) 3 pints (1.5 qt) . No issues, shifts very nicely.

Wow… it’s great to see that the shift nob looks like it may have been offered at new-make… I thought perhaps my PO had changed it.


I also one very similar but the ears are pointed outwards laying down. I noticed a similar cat on an xk 120 (iirc). I send a picture when I get home……

Those are all after market. It could be the selling dealer installed it, but the car didn’t leave the factory in Coventry with it.

I believe these knobs were made by Amco. They were available in leather or wood. Here is a 1970 ad showing two Jaguar knobs.

Amco also had a chrome cloisonné knob that occasionally come up for sale on Ebay. I found and installed one on my car - more bling! Here is their 1962 ad.

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I think this came up a few weeks ago in another thread.

For any gearbox with brass, bronze or other soft metal in the synchromesh, it’s better to use the lowest GL value MTL. The GL indicates how much extreme pressure, EP, additive is present. The additive sticks to the surface and acts as a sacrificial protection. Essentially, the additive is worn or ground away instead of the material underneath it. However, if there’s a lot of additive on a metal that’s not so hard, the material beneath the additive surface comes away with it and wear increases. Moreover pressure levels are not so high in normal gearbox designs like the old Jaguar 4-speeds. I’d use a GL-4 in both. It’s a case where for once less really is more.

Mine is the MG one: wonder what it’d bring on eBait?


They are both GL-4.

Basically, if your gearbox originally called for something like 30 wt or 20W-50 engine oil, you use MTL. If your gearbox originally called for 80W-90 gear oil, you use MT90.

I’m a big fan of Driven brand gear oils, as they have consistently worked better than MT90 (in my opinion) in several back-to-back tests across multiple gearboxes.

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those shift knobs were sold at every auto parts store. sitting on the counter as you checked out. thats how i bought mine 1975. black leather w growler.
somewhere around 1980 i installed a Nardi wood steering wheel.

That has to be ugliest pissed off cat I ever .

Looks like a devil’s face.

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Looking GREAT Rick!!

Best Regards,

Back to the OP…Motorcraft Full Synthetic Manual Transmission Fluid. It’s the only thing (including RedLine) that quieted (slightly) my noisy reverse idler

Jim, I also switched to Motorcraft tranny fluid. It is slightly easier to shift. A good replacement gearbox oil.


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How about quieting howling 1st and 2nd gears? Gear changes are fine.

I wouldn’t count on a major improvement. As I mentioned above, a slight quieting of my reverse idler which is kind of a rattle when the car is idling in neutral with the clutch out. Can’t hurt to try it, though.

motorcraft for which gearbox?